Nuclear energy density optimization: Large deformations

TL;DR

This paper introduces a new nuclear energy density functional optimized for large deformations, improving the description of fission barriers while maintaining accuracy for nuclear masses and separation energies.

Contribution

The authors developed a new Skyrme-like energy density functional using a derivative-free optimization method, enhancing modeling of strongly elongated nuclei and fission barriers.

Findings

Improved description of fission barriers in 240Pu.

Maintained accuracy for nuclear masses and separation energies.

Demonstrated importance of large deformation states in parameterization.

Abstract

A new Skyrme-like energy density suitable for studies of strongly elongated nuclei has been determined in the framework of the Hartree-Fock-Bogoliubov theory using the recently developed model-based, derivative-free optimization algorithm POUNDerS. A sensitivity analysis at the optimal solution has revealed the importance of states at large deformations in driving the parameterization of the functional. The good agreement with experimental data on masses and separation energies, achieved with the previous parameterization UNEDF0, is largely preserved. In addition, the new energy density UNEDF1 gives a much improved description of the fission barriers in 240Pu and neighboring nuclei.